Inventors:
Daniel Alan Brokenshire - Round Rock TX
Suzanne Carol Deffeyes - Austin TX
Gordon Clyde Fossum - Austin TX
Barry L. Minor - Austin TX
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06T 1540
Abstract:
A method of and system for testing a graphic primitive for trivial acceptance or rejection. An initial bounding volume, such as a rectangular parallelepiped, is defined by the graphic primitive's maximum and minimum x, y, and z coordinates in an initial coordinate system. A first bounding volume is then defined by the graphic primitive's maximum and minimum x', y', and z' coordinates in a first coordinate system, where the first coordinate system is transformed with respect to the initial coordinate system. Preferably this transformation comprises a 45. degree. rotation about a common axis such as the z-axis. The initial bounding volume and the first bounding volume are then intersected to form a modified bounding volume. The vertices of the modified bounding volume are then available for use in determining whether the graphic primitive may be trivially rejected or accepted within a specified viewing volume. In one embodiment, the method further includes defining and using a second modified bounding volume by intersecting the initial bounding volume with a second bounding volume defined by the graphic primitive's maximum and minimum x", y", and z" values in a second coordinate system.